Field of the Invention
The present invention relates to a measurement apparatus that measures a position of a mark on a substrate, a lithography apparatus, and a method of manufacturing an article.
Description of the Related Art
A lithography apparatus used to manufacture a semiconductor device or the like needs to measure the position of a mark on a substrate stage (mark provided on a substrate or the substrate stage) with high accuracy in order to position the substrate with high accuracy. The position of the mark is determined based on an image of the mark that is obtained by an imaging device.
An error arising from sampling (so-called sampling error) at the pixel pitch of the image sensor of the imaging device may be generated in measurement of the position of a mark. Japanese Patent Laid-Open No. 2001-66111 proposes a method of reducing a sampling error by using the fact that the sampling error appears in a predetermined period. The method described in Japanese Patent Laid-Open No. 2001-66111 reduces the sampling error by using a plurality of images in which the positions of a mark projected on the image sensor are different from each other depending on the period of the sampling error.
In the method described in Japanese Patent Laid-Open No. 2001-66111, a plurality of images are obtained by imaging a mark on a substrate while changing the position of a stage that holds the substrate. However, the position of the stage upon imaging the mark on the substrate may have a deviation from a target position. Reduction of the sampling error by using a plurality of images may become insufficient unless the movement of the substrate stage is controlled in consideration of this deviation.